It’s not top thickness, that’s only 3 layers and the bulge is on more layers than that.
Printed with PLA, 4 perimeters, 15% gyroid, but no infill makes difference, i don’t think this is about shell thickness.
Retraction is good, there is no oozing on retract moves and no stringing on the printed parts.
Otherwise the prints come out okay so i’m a bit stuck with this one!
You can see the bulging in all three edges on the picture, about 3-4mm from top to bottom, then a few ok layers, then again a few layers with bulges on corners.
Slicer is Prusa if that’s relevant.
Any ideas are welcome!
Yes. Get something like the TBG S or TBG Lite. These things are tiny, light, have a massive gear reduction (~1:11), which trades unnecessary speed (E is always running really slow even if you print really fast) for strength, and they have huge dual gears driving the filament. With that you can extrude TPU as if it was PLA.
If you can't find a fitting mount, I made one for the TBG Lite. PM me with some address where I can send you an STL if you are interested.